This one definitely sounded too good to be true from the start. A little bit of apple cider vinegar daily for young persons with obesity supposedly produced lower body weight, BMI, body fat ratio, blood sugar, triglycerides, and cholesterol. No side effects. However, this stunning piece of research on apple cider vinegar in obesity was indeed too good to be true and so the BMJ group retracted it on Tuesday. It had originally appeared in BMJ Nutrition, Prevention & Health 18 months ago..

James Heathers, Director of the Medical Evidence Project, pointed out that if the results of this study were real, apple cider vinegar would be 50 percent more effective than GLP-1 agonists such as semaglutide.

Multiple Problems

For anyone paying attention, the retraction is no big surprise. For years, we have been skeptical about the fantastical claims promoted by the apple cider vinegar fan club. And for this study in particular, warning signals flashed very quickly.

Heathers published a forensic review of the now retracted paper within two months of its original publication in March 2024. He identified problems with data availability, unlikely data distributions, randomization issues, statistical analysis flaws, improbable effect sizes, and more. His review prompted concern from other scientists and they submitted a letter of concern to the journal in June. It took the journal eight months to publish that letter. That’s twice as long as the journal took to review and publish the research itself.

The Wrong Decision

One of the red flags for this paper was the lack of a clinical trial registration. Publication ethics and integrity require this for any human trial to be published in a scientific journal. Martin Kohlmeier, editor-in-chief for BMJ Nutrition, Prevention & Health, concedes in hindsight that the decision to publish without a trial registration “was the wrong decision to make.”

Andrew Brown, Director of Biostatistics for the Arkansas Children’s Research Institute, said:

“I am glad to see the retraction of this paper to uphold the integrity of the field, but we need to do better in the field of nutrition to register, design, conduct, and report trials to a high standard before publication.”

The Residue of Misinformation

Unfortunately, this retracted paper leaves a residue of misinformation that will not completely disappear. Just this week, a new systematic review and meta-analysis appeared in Nutrients regarding apple cider vinegar in obesity. And yes, it relied in part on the invalid data from the now retracted study to conclude:

“These findings suggest that daily intake of apple cider vinegar may represent a valuable aid in obesity management, offering a more affordable option with fewer side effects compared to pharmacological treatments for obesity.”

This is how bogus ideas live on despite evidence that they are nonsense. We’re seeing a lot of that lately.

Click here for the retraction notice and here for excellent reporting from Retraction Watch about this sorry mess.

Apple Cider Vinegar, photograph by Veganbaking.net, licensed under CC BY-SA 2.0